If your having trouble with permanant marker on your Nes carts(etc.):
use Crud-Cutter( im pretty sure thats spelled wrong) for really dificult marker,
but that stuff MELTS black Genny cart plastic is left sit for a couple seconds.
Goo-Gone is pretty awsome for getting off anything. I got a Godzilla cart at CGE that was encrusted with bird-poop. It looks brand new now!